The present invention relates to azo dye of formula I

##STR00001##

defined in claim 1, to a liquid crystalline medium comprising said azo dye, the use of said medium for optical, electrooptical and electronic purposes, in particular in devices for regulating the passage of energy from an outside space into an inside space, for example in windows. The invention further relates to a device containing the liquid crystalline medium according to the invention.

The present invention relates to compositions comprising a combination of benzothiadiazole and thiadiazoloquinoxaline derivatives, to liquid-crystalline media containing the compositions, and to the use of the compositions and the media in optical, electronic and electro-optical devices, in particular in devices for regulating the passage of energy from an outside space into an inside space, for example in switchable windows.

The present invention relates to liquid crystal (LC) media comprising one or more polymerisable compounds as further specified in the description or claims and a self-alignment additive for vertical alignment. The media are adapted for use in LC displays, especially in LC displays of the polymer-sustained alignment type.

A compound is represented by general formula (I), a liquid-crystal composition contains this compound, and devices are made using this liquid-crystal composition. Having a large refractive-index anisotropy Δn and a sufficiently high Tni, highly compatible with liquid-crystal compositions, and exhibiting a high dielectric anisotropy in the radio frequency range, the compound is a useful material for RF phase shifters, phased-array antennae, image recognition devices, distance meters, liquid-crystal displays, liquid-crystal lenses, and birefringent lenses for 3D image display, among other devices. ##STR00001##

The present invention relates to a cholesteric liquid crystalline (LC) medium for a Polymer-Network Liquid Crystalline (PNLC) light modulation element, to a method of its production and to the use of such cholesteric LC media in PNLC light modulation elements. Furthermore, the present invention relates to PNLC light modulation elements, as such, to a method of their production, to the use of such light modulation elements in optic or electro optic devices, in particular in LC displays, and to optic or electro optic devices comprising such light modulation elements according to the present invention.

A LC lens and a liquid-crystal medium used in said LC lens, wherein the medium contains one or more compounds of each of formulae I and II ##STR00001##

The invention relates to a compound of formula I,

##STR00001##

wherein R.sup.11, R.sup.21, A.sup.11, A, Z, X.sup.11, X.sup.21, Y.sup.11, Y.sup.12, Sp.sup.11, Sp.sup.21, o and p have one of the meanings as given in claim 1. The invention further relates to method of production of a compound of formula I, to the use of said compounds in LC media and to LC media comprising one or more compounds of formula I. Further, the invention relates to a method of production of such LC media, to the use of such media in LC devices, and to LC device comprising a LC medium according to the present invention. The present invention further relates to a process for the fabrication such liquid crystal display and to the use of the liquid crystal mixtures according to the invention for the fabrication of such liquid crystal display.

The invention relates to a liquid-crystalline medium having a nematic phase comprising one or more compounds of formula X

##STR00001##

wherein the parameters have the meaning given in the text,
to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type and to the use of the compounds of formula X for improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds, as well as to certain compounds of formula X, as specified in the text.

A liquid-crystalline medium which comprises at least one compound selected from the group of compounds of the formulae IA to IH,

##STR00001##

in which Z.sup.1 denotes a single bond, —CH.sub.2CH.sub.2—, —CH═CH—, —CH.sub.2O—, —OCH.sub.2—, —CF.sub.2O—, —OCF.sub.2—, —COO—, —OCO—, —C.sub.2F.sub.4—, —(CH.sub.2).sub.4—, —CHFCHF—, —CF.sub.2CH.sub.2—, —CH.sub.2CF.sub.2—, —C≡C—, —CF═CF—, —CH═CHCHO— or —CH.sub.2CF.sub.2O—,
and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PALC, FFS, PS-FFS, SA-VA, PS-IPS or IPS effect.

A positive dielectric anisotropic liquid crystal composition includes one or more compounds of formula I and one or more compounds of formula II: ##STR00001##
wherein R1 represents cyclopropyl, cyclobutyl or cyclopentyl, R2, R3 and R4 are as defined in the specification, and a liquid crystal display device. The liquid crystal composition has positive dielectric properties, a high charge retention ratio, a low rotary viscosity, a fast response time, and especially a high transmittance, and is suitable for manufacturing a TFT-LCD with a high transmittance and a fast response.